Tbh i think you need to chalk that up to dog being dogs.
If my dog was off the lead and bit another dog of lead while playing, or was bitten by one, I'd take it on the chin.
If the other dog was playing fetch it was likely defensive of its ball, no wonder your dog got little bite for going and bothering it. Sorry but it's on you.
Ps. I'm sorry, I hope your dog is okay, it's distressing.
Tbh i think you need to chalk that up to dog being dogs.
If my dog was off the lead and bit another dog of lead while playing, or was bitten by one, I'd take it on the chin.
If the other dog was playing fetch it was likely defensive of its ball, no wonder your dog got little bite for going and bothering it. Sorry but it's on you.
Ps. I'm sorry, I hope your dog is okay, it's distressing.